Quantitative XPS of plutonium: Evaluation of the Pu4f peak shape, relative sensitivity factors and estimated detection limits

High-resolution X-ray photoelectron spectra have been acquired from sputter cleaned and in situ oxidized samples of alpha-plutonium and a face-centred cubic delta-plutonium-gallium alloy. The differences in the Pu4f peak shape in these two materials have been investigated, and the poorly screened satellite peaks have been quantified. Curve fitting parameters for the Pu4p(3/2), Pu4d(5/2), Pu4f and Pu6p(3/2) photoelectron peaks are reported, and relative sensitivity factors have been determined. The Pu4f curve fit model has been applied to data acquired using different spectrometers and alloys. Examples of quantification of the plutonium spectra are provided and minimum detection limits are calculated for common impurities in plutonium metal.